Method and apparatus for cutting pins for producing chain links

ABSTRACT

The production of pins which subsequently are to be bent and welded to form chain links, in which each pin is cut off a rod by a pair of equal wedge-shaped blades which are simultaneously reciprocated in opposite directions to each other within a common central plane extending transverse to the axis of the rod, and which while cutting impress V-shaped notches into diametrically opposite sides of the rod so that the ends of each pin have an angular shape similar to a peaked roof. One preferred embodiment of the invention provides that, instead of forcing the two blades so deeply in the material that their cutting edges engage with each other and thus cut off each pin completely, the blades are impressed only for such a distance into the material that a thin connecting web-remains between the pin and the rod supply which web is then shorn off by moving the pin transversely relative to the rod.

[ 1 Sept. Il, 1973 METHOD AND APPARATUS FOR CUTTING PINS FOR PRODUCINGCIIAIN LINKS [75] Inventor: Gerhard Lange,Reutlingen,

Germany [73] Assignee: Wafios Maschinen fabrik Wagner,

Fielter & Sehmid G.m.b.II., Reutlingen, Germany [22] Filed: May 28, 1971{21] Appl. No.: 147,986

[30] Foreign Application Priority Data June 18, 1970 Germany P 20 29865.1

[56] References Cited UNITED STATES PATENTS 2,057,928 10/1936 Stahl83/51 2,613,719 10/1952 Conrad 83/560 X 845,331 2/1907 Briede 83/623 X1,559,082 [0/1925 Friederici ..83/600X Primary Examiner-Donald R. SchranAssistant ExaminerJames F. Coan Att0rneyArthur O. Klein [57] ABSTRACTThe production of pins which subsequently are to be bent and welded toform chain links, in which each pin is cut off a rod by a pair of equalwedge-shaped blades which are simultaneously reciprocated in oppositedirections to each other within a common central plane extendingtransverse to the axis of the rod, and which while cutting impressV-shaped notches into diametrically opposite sides of the rod so thatthe ends of each pin have an angular shape similar to a peaked roof. Onepreferred embodiment of the invention provides that, instead of forcingthe two blades so deeply in the material that their cutting edges engagewith each other and thus cut off each pin completely, the blades areimpressed only for such a distance into the material that a thinconnecting web-remains between the pin and the rod supply which web isthen shorn off by moving the pin transversely relative to the rod.

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ATro KNEY METHOD AND APPARATUS FOR CUTTING PINS FOR PRODUCING CIIAINLINKS The present invention relates to a method and an apparatus forperiodically cutting pins with ends of an angular shape similar to apeaked roof off a rod or wire of a greater length for subsequentlyproducing chain links therefrom.

The conventional manner of producing the pins which are subsequently tobe bent to form chain links consists in cutting these pins by means ofshears off a longer rod or wire. The ends of each pin then havesubstantially plane surfaces which are undesirable for buttwelding themtogether after the pin has been bent. It has therefore already beenproposed to saw or mill notches of a triangular shape into two oppositepoints of the rod so that the ends of each pin will then have an angularshape similar to a peaked roof. Although pin ends of such a shape arevery suitable for butt-welding them together after the respective pinhas been bent into a link shape, this manner of producing such pin endsis much too expensive at least in all cases in which the links are madeof a rod stock of a moderate thick ness.

It is an object of the present invention to provide a very inexpensivemethod and a simple apparatus for cutting sections off a rod or wire soas to form pins each of which is provided by this cutting operation witha pair of opposite ends of an angular shape similar to a peaked roof,which has been found to be the most suitable shape for welding the twoends together after the pin has been bent into a link shape.

According to the invention, this object is attained by cutting the pinsoff a rod or wire by a cutting operation which does not involve theremoval of any material and in which the ends of adjacent pins are cutby forming angular notches at diametrically opposite points of the rod.

The formation of such notches according to the invention during theoperation of cutting off the pins is not more expensive than the usualcutting operation by means of shears either insofar as the cost of thenecessary machine or the length of time for the cutting operation isconcerned. When such roof-shaped ends are weldedtogether, the weldproduced has a similar quality and requires a similar length of time asthe weld between two spherically rounded ends which can only be producedat considerable expense, because in each case the adjacent ends arewelded by being heated from the inside toward the outside.

According to one feature of a preferred embodiment of the invention,each notch is impressed into the rod to a depth which is smaller thanone half of the diameter of the rod so that a small web will remainbetween the two notches which may then be broken off by moving the twoends of the rod which are connected'by the web relative to each other ina direction transverse to the longitudinal direction of the rod. Thebroken surface which is thus produced is substantially plane and thissurface together with the flanks of the notches causes the roof-shapedends of each pin to be of a trapezoidal shape. Such a shape has theconsiderable advantage that no burrs or ridges will be formed on thepoints of separation which might break off during the subsequent workand might lead to interferences in the operation of the machinescarrying outthis work, or which might burn off during the weldingoperation and might cause the welded part of each link to have an unevenstructure which would impair the solidity of the weld and thus of theentire link. lt is another advantage of this manner of cutting off theindividual pins that, when the pin is bent into a link shape and itsends are pressed against each other during the welding operation, theseends cannot slide past each oher and will thus not be bent out of axialalignment with each other, as it may occur if the ends are of abladelike shape and their sharp edges do not accurately meet each other.

The apparatus according to the invention for carry ing out the newmethod comprises a pair of opposite notchingblades which are movableback and forth in opposite directions within a common plane whichextends transversely to the axis of the rod to be cut and at rightangles to the directions of the cutting edges of these blades which arelikewise disposed within the same plane so as to face each other.

By means of such notching blades it is easily possible while severingeach pin from a rod to impress triangular notches into the adjacent endsof the rod and pin so that each free end will then have an angular,substantially roof-shaped form.

Another feature of the invention consists in providing suitable meansfor clamping the rod in a fixed position at a point which is spaced at acertain distance from its free end from which immediately thereafter apin of a predetermined length is cut by the blades, and in mounting theblades so as to permit them because of the wedging action exerted bythem upon the pin during their cutting movement to move as a unittogether with the pin for a short distance in the axial forwarddirection of the latter. Due to this manner of mounting the blade unit,the material of the end of the rod and of the adjacent end of the pinwill be only slightly compressed despite the wedging action which, dueto their shape, the blades exert during the cutting operation upon thismaterial and the blades will therefore not be subjected to any stressesin their transverse directions and only very low power will be requiredfor driving the blades toward each other and into the rod material so asto cut offieach pin.

Another feature of the invention consists in the provision of simplemeans for returning the blade unit after the cutting operation to itsoriginal postiion. These means may consist, for example, of a springwhich then shifts this unit back to this position in which it engageswith a fixed stop.

According to a preferred embodiment of the invention which is ofadvantage because of its simplicity of construction, the two notchingblades are mounted on a pair of arms which are pivotable relative toeach other and are together slidable along their pivot axis and adaptedduring the cutting operation to move like the arms of a pair of shears.

If the opposite notches are impressed into the rod to a depth so that acentral web-remains between them this web may be broken off while thetwo rod sections are still mounted in the cutting apparatus. lt is forthis purpose only necessary to provide a pressure element which isadapted to exert a pressure upon one of the two rod sections at a pointdirectly adjacent to the notching blades and in a direction transverseto the longitudinal direction of the latter and in the longitudinaldirection of the cutting edges of the blades, and to provide a solidsupport for the other rod section which likewise supports the latterdirectly adjacent to the notching bladcs at the side of the rod oppositeto that upon which the pressure is exerted.

The features and advantages of the present invention will become moreclearly apparent from the following detailed description thereof whichis to be read with reference to the accompanying drawings, in which:

FIG. 1 shows diagrammatically and partly in cross section a side view ofthe essential elements of the apparatus according to a first embodimentof the invention;

FIG. 2 shows an end view of the notch-cutting mechanism without itshousing, and of its driving means;

FIG. 3 shows a view similar to FIG. 1 of an apparatus according to asecond embodiment of the invention; while FIG. 4 shows an enlarged viewof the notching blades of the apparatus according to FIG. 3 in theirposition of the deepest penetration into the rod.

Referring first particularly to FIGS. 1 and 2 of the drawings, theapparatus according to the invention for producing pins 1 of an equalbut adjustable length, each of which is subsequently to be bent into theshape of a chain link and the abutting ends of which are then to bewelded together, comprises a pair of notching blades 3 and 4 which aremovable back and forth in opposite directions to each other within acommon plane which extends transversely to the axis of the rod 2 fromwhich the pins 1 are to be cut. These two blades 3 and 4 are equallywedge-shaped and terminate in cutting edges facing each other. The bladeangle of each of these blades 3 and 4 is made as acute as possible,although large enough so that the blades will be sufficiently resisantto wear and breakage.

As illustrated more in detail in FIG. 2, each of the two equal notchingblades 3 and 4 is mounted on one arm of a two-armed lever 6 or 7,respectively, and in a manner so as to be easily removed and exchanged,and both of these levers are pivotable relative to each other about theaxis ofa common shaft 5. The ends of the two other arms of levers 6 and7 which are drawn toward each other, for example, by a tension spring,not shown, carry rollers 8 and 9 which are rotatable'about parallel axesand engage at all times upon the cam surfaces of a cam plate 10 which ispivotable about the axis of a fixed shaft or pivot pin 11. This camplate 10 has a radially projecting arm 12 which is pivotably connectedto one end of a connecting rod 13 which is driven by an eccentric 23which is mounted on a drive shaft 24. Thus, at each revolution of driveshaft 24, cam plate 10 will be pivoted back and forth about the axis ofshaft 11 and will thereby pivot the levers 6 and 7 equally in oppositedirections to each other so that both notching blades 3 and 4 will bemoved at the same speed and alternately toward or away from each other.If desirable, it is also possible by a suitable design of the crank andcam drive of levers 6 and 7 to carry out the cutting strokes of blades 3and 4 at a speed different from that of their retracting strokes.

Levers 6 and 7 are slidable axially along the shaft 5, but only togetheras a unit and for equal distances so that the cutting edges of blades 3and 4 will always remain within a common plane and point directly towardeach other. Suitable means which are indicated diagrammatically in FIG.1 in the form of a compression spring 14 tend to maintain the levers 6and 7 in engagement with a stationary stop member 15 which is mounted atthe side of the levers preceding the cutting position of blades 3 and 4,as seen in the direction in which rod 2 is fed periodically for equaldistances by a feeding mechanism, not shown. Spring [4 acts upon theother side of one or both levers 6 and 7 and is mounted on a stationarypart 16 of the cutting mechanism which is indicated generally by thenumeral 17.

At the other side of the stop member 15 a clamping mechanism 18 ismounted which is adapted to clamp the rod or wire 2 in a fixed positionduring each cutting operation of blades 3 and 4. This clamping mechanismconsists of a stationary clamping jaw 19 and a second clamping jaw 20which is adapted to be reciprocatcd relative to the jaw l9 by means ofacam plate 2] which is also mounted on drive shaft 24 and rolls along aroller 26 which is rotatable on one end of an arm 22 and held inconstant engagement with cam plate 21 by a spring, not shown, which actsupon the arm 22, while the other end of this arm is connected to theclamping jaw 20. Since the reciprocating movements of clamping jaw 20and those of blades 3 and 4 are derived from the same drive shaft 24,they may be easily timed in relation to each other so that the rod orwire 2 will be clamped between jaws l9 and 20 just before blades 3 and 4while moving toward each other engage upon rod 2 which will then remainclamped until the blades after cutting off the pin 1 are being retractedand have completely disengaged from the adjacent ends of rod 2 andpin 1. As soon as rod 2 is then released by the retraction of clampingjaw 20, the feed mechanism as previously mentioned will shift the rodforwardly for the distance required for cutting off the next pin 1, and,unless the last-formed pin 1 is not withdrawn, from the cuttingmechanism 17 in the manner as subsequently described for being conveyed,for example, to a station in which it is bent into a link shape, theangular roof-shaped end of rod 2 will abut against the equally shapedend of this pin 1 and will eject the latter from the cutting mechanism.

Instead of being thus ejected from the cutting mechanism 17 by the nextfeeding movement of rod 2, pin 1 may be gripped by tongs 25 immediatelybefore it is completely severed from rod 2. As soon as this occurs,these tongs 25 which are only illustrated diagrammatically in FIG. 1will carry the pin 1 to a mechanism, not shown, in which the pin is bentinto the shape of a chain link and in which, if desired, the two angularends of pin 1 which then abut against each other may also be weldedtogether.

After the two levers 6 and 7 have been pivoted relative to each other soas to disengage the blades 3 and 4 completely from the front end of rod2, spring 14 moves levers 6 and 7 again into engagement with stop member15.

The same cycle of operations is then repeated, the clamping jaw's l9 and20 will again clamp the rod or wire 2 in a fixed position, and blades 3and 4 will again be equally moved toward each other and will therebyimpress two opposite notches into the wire until their cutting edgesengage with each other and the next pin 1 is thus cut off. Due to thenotching action of blades 3 and 4 upon rod 2 during this cuttingoperation, the adjacent ends of rod 2 and pin 2 will again be inclinedfrom both sides similar to peaked roofs, and due to the wedging actionof the blades upon the rear end of pin 1 this pin together with blades 3and 4 and levers 6 and 7 carrying the latter will be shifted forwardlyagainst the action of spring 14 and thus away from stop member 15 andthe clamping mechanism 18.

The apparatus according to the second embodiment of the invention asillustrated in FIGS. 3 and 4 is adapted to produce the adjacent ends ofthe rod or wire sections 101 and 102 to be of a trapezoidal shape. Thecutting mechanism 117 is for this purpose designed so that, when the twonotching blades 103 and 104 are equally impressed to their deepestpoints of penetration into the material, their cutting edges will stillbe spaced at a small distance from each other. This distance which mayamount, for example, to one quarter of the diameter of the rod or wire102 from which the pins 101 are to be severed is adjustable by means ofscrews 103' and 104'. Blades 103 and 104 may be locked in the adjustedpositions on the levers 106 and 107 by means of screws 127 which whichextend transversely through the two blades and into the levers.

Since the blades 103 and 104 do not penetrate as deeply into the rod orwire as the blades 3 and 4 according to FIGS. 1 and 2, the blade angleof each blade 103 and 104 may be slightly larger than that of each blade3 and 4 even though the maximum width of the notches which both kinds ofblades impress into the rod material may be equal. Such blades 103 and104 with a wider blade angle have the advantage of being moreresistantto wear and breakage.

Since the cutting edges of the blades 103 and 104 at the point of theirdeepest penetration into the rod material are still spaced at a certaindistance from each other, the rod section 101 will still be connected tothe main rod section 102 by a central web. For severing this web, theapparatus according to FIG. 3 is provided with a two-armed pressurelever 124 which is pivotable about an axis 125 which is located betweenthe drive shaft carrying the cam plate 121 and the eccentric 123 and therod or wire 102 and extends parallel to the axes of this shaft and rod102. By means of a pin 124', the outer end of lever 124 is adapted topress upon the jaw 125' of the tongs 125 in a direction transverse tothe longitudinal direction of rod section 101 which is to be severedfrom rod 102 and substantially in the longitudinal direction of thecutting edges of the two blades 103 and 104. Since tongs 125 grip therod section 101 closely adjacent to blades 103 and 104, the force whichwill be exerted by lever 1124 upon this rod section consistssubstantially only of a shearing force.

At the other side of and immediately adjacent to blades 103 and 104, theend of rod 102 from which the section 101 is to be severed which issubsequently to be bent into the shape of a chain link is rigidlysupported by a member 126 which serves as an anvil. This end of rod 102is thus rigidly held when the connecting web between the two rodsections 101 and 102 is broken off and rod 102 is therefore preventedfrom bending.

The pivoting movement of lever 124 for exerting a pressure upon jaw 125of tongs 125 is produced by a cam 128 which is mounted on cam plate 121and acts upon the associated arm of lever 124. After lever 124 hascarried out its pivoting pressure movement under the action of cam 128,the lever is returned to its original position by the action of aspring, not shown.

Of course, the pressure lever 124 may also be driven by any othersuitable means, for example, by a separate cam plate.

In all other respects, the apparatus according to FIG. 3 may be of thesame construction as the apparatus ac cording to FIGS. 1 and 2.

Although my invention has been illustrated and described with referenceto the preferred embodiment thereof, I wish to have it understood thatit is in no way limited to the details of such embodiment but is capableof numerous modifications within the scope of the appended claims.

Having thus fully disclosed my invention, what I claim is:

1. An apparatus for producing pins with wedgeshaped ends forsubsequently producing chain links therefrom, comprising a pair ofnotching blades each having a substantially V-shaped cross-section withan apex facing that of the other blade, and means for slidably mountingsaid blades and for reciprocating them in opposite directions to eachother within a common plane extending transverse to the axis of a rodfrom which a pin is to be cut by said blades so that each blade isimpressed into said rod substantially up to the longitudinal axis ofsaid rod and a section is cut off said rod to form one of said pins whenboth blades reach said axis of said rod the adjacent ends of said rodand said pin then having said angular shape, means for clamping said rodin a fixed position at a point at the rear of said blades, stationarystop means between said clamping means and said blades for determiningthe normal position of said blades prior to impressing said blades intosaid rod, mounting said blades so as to be slidable together as a unitfor a limited distance from said stop means in the axial direction ofsaid rod so that, while said blades are being impressed into said rod,the unclamped section of said rod in front of said blades will yieldtogether with said blade unit in said axial direction away from saidstop means because of the V-shape of said blades, and means forreturning said blade unit to said normal position after said section ofsaid rod forming a pin has been cut off by said blades.

2. An apparatus as defined in claim 1, in which said returning meanscomprise atleast one spring acting upon said blade unit, said springunit being yieldable in said axial direction against the action of saidspring.

3. An apparatus for producing pins with wedgeshaped ends forsubsequently producing chain links therefrom, comprising a pair ofnotching blades each having a substantially V-shaped cross-section withan apex facing that of the other blade, and means for slidably mountingsaid blades and for reciprocating them in opposite directions to eachother within a common plane extending transverse to the axis of a rodfrom which a pin is to be cut by said blades so that each blade isimpressed into said rod substantially up to the longitudinal axis ofsaid rod and a section is cut off said rod to form one of said pins whenboth blades reach said axis of said rod the adjacent ends of said rodand said pin then having said angular shape, said means for slidablymounting and reciprocating said blades comprising a shaft mounted in afixed position, and comprising a pair of two-armed levers mounted onsaid shaft so as to be pivotable in opposite diections to each otherabout said shaft and also to be slidable together as a unit along saidshaft in its axial direction, means for removably securing said bladesto the arms of said levers at one side of said shaft, and means formoving both other arms of said levers equally toward and away from eachother and for thereby moving said blades ac- 5. An apparatus as definedin claim 4, in which said cordingly. second member forms a lever whichis pivotable in re- 4. An apparatus as defined in claim 3, in which saidsponse to the movements of said blades. first member forms a stationarysupporting member.

1. An apparatus for producing pins with wedge-shaped ends forsubsequently producing chain links therefrom, comprising a pair ofnotching blades each having a substantially V-shaped crosssection withan apex facing that of the other blade, and means for slidably mountingsaid blades and for reciprocating them in opposite directions to eachother within a common plane extending transverse to the axis of a rodfrom which a pin is to be cut by said blades so that each blade isimpressed into said rod substantially up to the longitudinal axis ofsaid rod and a section is cut off said rod to form one of said pins whenboth blades reach said axis of said rod the adjacent ends of said rodand said pin then having said angular shape, means for clamping said rodin a fiXed position at a point at the rear of said blades, stationarystop means between said clamping means and said blades for determiningthe normal position of said blades prior to impressing said blades intosaid rod, mounting said blades so as to be slidable together as a unitfor a limited distance from said stop means in the axial direction ofsaid rod so that, while said blades are being impressed into said rod,the unclamped section of said rod in front of said blades will yieldtogether with said blade unit in said axial direction away from saidstop means because of the V-shape of said blades, and means forreturning said blade unit to said normal position after said section ofsaid rod forming a pin has been cut off by said blades.
 2. An apparatusas defined in claim 1, in which said returning means comprise at leastone spring acting upon said blade unit, said spring unit being yieldablein said axial direction against the action of said spring.
 3. Anapparatus for producing pins with wedge-shaped ends for subsequentlyproducing chain links therefrom, comprising a pair of notching bladeseach having a substantially V-shaped cross-section with an apex facingthat of the other blade, and means for slidably mounting said blades andfor reciprocating them in opposite directions to each other within acommon plane extending transverse to the axis of a rod from which a pinis to be cut by said blades so that each blade is impressed into saidrod substantially up to the longitudinal axis of said rod and a sectionis cut off said rod to form one of said pins when both blades reach saidaxis of said rod the adjacent ends of said rod and said pin then havingsaid angular shape, said means for slidably mounting and reciprocatingsaid blades comprising a shaft mounted in a fixed position, andcomprising a pair of two-armed levers mounted on said shaft so as to bepivotable in opposite diections to each other about said shaft and alsoto be slidable together as a unit along said shaft in its axialdirection, means for removably securing said blades to the arms of saidlevers at one side of said shaft, and means for moving both other armsof said levers equally toward and away from each other and for therebymoving said blades accordingly.
 4. An apparatus as defined in claim 3,in which said first member forms a stationary supporting member.
 5. Anapparatus as defined in claim 4, in which said second member forms alever which is pivotable in response to the movements of said blades.